336
THE DISCOVERY OF THE CHILD
As for the remaining five, it is the half of ten, and if we had
cut the long piece into two equal parts that would be dividing ten
by two. In writing this would be:
10-4=6
103=7
102=8
101=9
10-2=5
Once the children have mastered these exercises they are multi-
plied, also by the spontaneous work of the children. Can we make
two pieces into a three? Let us put the one on the two, and then
let us write in order to remember the completed exercise: 2+1=3.
Can a four be made from two pieces? 3+1=4; 43=1; and
41=3.
The piece of two bears the same relationship to four as the
five does to the ten; that is, when used twice over it goes from one
end to the other, it enters into it exactly twice: 4+2=2; 2x2=4.
Take this problem. Let us see with how many pieces we can do
this game: the three does it with six, and the four with eight,
thus
2x2=4; 3x2=6; 4x2=8; 5x2=10; and
10-5-2=5; 8-2=4; 6+2=3; 4+2=2.
At this point help may be got from the small cubes used in
the game for memorizing numbers.
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